1. Field of the Invention
The present invention relates to a chemically amplified resist composition and a chemically amplified resist composition for immersion lithography, and more specifically relates to a chemically amplified positive resist composition and a chemically amplified positive resist composition for immersion lithography which are used in semiconductor microfabrication.
2. Background Information
Lithographic exposure sources that are used in semiconductor microfabrication include g rays (wavelength of 436 nm), i rays (wavelength of 365 nm), KrF excimer lasers (wavelength of 248 nm), ArF excimer lasers (wavelength of 193 nm), F2 excimer lasers (wavelength of 157 nm), and extreme ultraviolet light (EUV) (wavelength of 13.5 nm). Immersion lithography, on the other hand, is another technique in which resolution and depth of focus are improved without changing the exposure wavelength. In immersion lithography, the space between the lens and photoresist is filled with a medium having a greater refractive index than air, thereby allowing a lens with a greater numerical aperture to be used.
In this type of lithographic process, a chemically amplified resist is normally used when a KrF or lower shortwave length light source is employed, and functional resin compositions which have been provided with a variety of repeating unit structures for better etching resistance, alkali development, substrate adhesion, and the like have been developed. The use of monomers with an adamantane structure has been proposed as unit structures in starting materials for functional resin compositions in order to ensure adequate resolution, line edge roughness, and the like in particular Patent Document: Japanese Patent Laid-open Publication No. 2006-16379 etc.